In this topic, it would be nice if you can post your current recommendations for software. Development, productivity, or anything.
Here's what I can personally recommend:
Installer - NSIS (free!)
2D Windows Game Development - Construct (free!)
Construct has been making great progress ever since it was initially released, and I support its development. Its ability to create games rapidly and without writing code is excellent.
2D Multiplatform (Windows, Mac, Linux, iPhone, Flash) Game Development - haXe (free!)
Developer to Developer Discussion - Yammer
Yammer is sort of like twitter for small groups of people. It's not free, but it's a great resource. We use it all of the time to share discussion between the few developers I network with closely, and it has a nice desktop client.
Sharing Files Easily - Dropbox
Dropbox has been a big productivity booster for us in the last two years as it has allowed us to share tons of development files quickly and without hassle. If you have not tried it out yourself now is the time to do so.